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 ###Instrução: Quando houve 8.9% de Green-Communist?
 ###Tabelas: CREATE TABLE opinion_polling (opinion_polling_id AUTO_INCREMENT PRIMARY KEY, Date Released VARCHAR, Polling institute VARCHAR, Socialist VARCHAR, Social Democratic VARCHAR, Peoples Party VARCHAR, Green-Communist VARCHAR, Left Bloc VARCHAR, Lead VARCHAR) CREATE TABLE biggest_losses (biggest_losses_id AUTO_INCREMENT PRIMARY KEY, Margin INT, Score VARCHAR, Opponent VARCHAR, Venue VARCHAR, Year INT) CREATE TABLE municipal_detachments (municipal_detachments_id AUTO_INCREMENT PRIMARY KEY, Municipality VARCHAR, Population INT, Police officers INT, Residents per officer INT, Total costs (2005) VARCHAR, Cost per capita VARCHAR, Case burden INT, Crime rate per 1,000 people INT, Police force VARCHAR) CREATE TABLE type_i (type_i_id AUTO_INCREMENT PRIMARY KEY, Part Number VARCHAR, Pins VARCHAR, Body Width/mm INT, Body Length/mm INT, Lead Pitch/mm INT) CREATE TABLE game_history (game_history_id AUTO_INCREMENT PRIMARY KEY, Year INT, Date VARCHAR, Television VARCHAR, Designated Visitors VARCHAR, Designated Home VARCHAR, Stadium VARCHAR, City VARCHAR)  
SELECT Date Released FROM opinion_polling WHERE Green-Communist = 8.9%